{"title":"Reply to the discussion on ^|^ldquo;A simple method for evaluation of jointed rock slope stability using slide surface approximated by piecewise linear^|^rdquo;","authors":"Taketomi Sumi, K. Sawada, A. Yashima","doi":"10.3208/JGS.9.775","DOIUrl":"https://doi.org/10.3208/JGS.9.775","url":null,"abstract":"","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":" 1229","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113946505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil liquefaction under initial shear stress induced by nearby slopes, embankments and superstructures causes large shear failure in the ground, leading to sliding, tilting and uneven settlement of the structures. In this study, a hollow torsional shear apparatus is used to investigate the effect of initial shear stress acting on horizontal plane on liquefaction behavior of medium to loose sand of relative density D r ≒ 30, 50% and fines content F c =0 ～ 30%. A series of test results have revealed that the liquefaction failure is categorized into five types; cyclic failure (CF) for α =0, cyclic biased failure (CBF) for small α , biased gradual failure (BGF) and biased sudden limited failure (BSLF) and biased sudden failure (BSF) for larger α . Among the 5 failure types, it is important to pay special attention to BSF type, which may develop abrupt strain increase due to initial shear stress by cyclic loading. In comparing with undrained monotonic loading tests, the mechanism of the abrupt BSF has been clarified. The angle of a yielding surface φ y ´ corresponding to the BSF has been studied under the effect of initial stresses for test specimens with different contractive behavior caused by parametrically changing fines content and relative density. It has been demonstrated that the BSF type failure is controlled by the angle φ y ´ reflecting contractive behavior of sand, irrespective of the magnitude of initial stress.
附近边坡、路堤和上部建筑引起的初始剪应力作用下的土壤液化，导致地面发生较大的剪切破坏，导致结构的滑动、倾斜和不均匀沉降。摘要利用空心扭剪仪，研究了水平面上初始剪切应力对相对密度D r≒30,50%，细粒含量F c =0 ~ 30%的中松散砂液化行为的影响。一系列试验结果表明，液化破坏可分为五种类型;当α =0时，循环失效(CF)，当α较小时，循环偏置失效(CBF)，当α较大时，偏置渐进式失效(BGF)和偏置突发性有限失效(BSLF)和偏置突发性失效(BSF)。在5种破坏类型中，需要特别注意的是BSF类型，它可能由于循环加载的初始剪切应力而产生突变应变增加。通过与不排水单调加载试验的比较，阐明了突变体滑移的机理。对细粒含量和相对密度随参数变化而产生不同收缩特性的试样，在初始应力的作用下，研究了屈服面φ y´对应的屈服面角。研究表明，与初始应力大小无关，BSF型破坏受反映砂土收缩特性的φ y´角控制。
{"title":"Effect of Initial Shear Stress on liquefaction failure and shear strain development by Hollow Cylindrical Torsional Shear Tests","authors":"R. Arai, T. Kokusho, T. Kusaka","doi":"10.3208/JGS.10.213","DOIUrl":"https://doi.org/10.3208/JGS.10.213","url":null,"abstract":"Soil liquefaction under initial shear stress induced by nearby slopes, embankments and superstructures causes large shear failure in the ground, leading to sliding, tilting and uneven settlement of the structures. In this study, a hollow torsional shear apparatus is used to investigate the effect of initial shear stress acting on horizontal plane on liquefaction behavior of medium to loose sand of relative density D r ≒ 30, 50% and fines content F c =0 ～ 30%. A series of test results have revealed that the liquefaction failure is categorized into five types; cyclic failure (CF) for α =0, cyclic biased failure (CBF) for small α , biased gradual failure (BGF) and biased sudden limited failure (BSLF) and biased sudden failure (BSF) for larger α . Among the 5 failure types, it is important to pay special attention to BSF type, which may develop abrupt strain increase due to initial shear stress by cyclic loading. In comparing with undrained monotonic loading tests, the mechanism of the abrupt BSF has been clarified. The angle of a yielding surface φ y ´ corresponding to the BSF has been studied under the effect of initial stresses for test specimens with different contractive behavior caused by parametrically changing fines content and relative density. It has been demonstrated that the BSF type failure is controlled by the angle φ y ´ reflecting contractive behavior of sand, irrespective of the magnitude of initial stress.","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"184 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121090603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Yamada, Y. Ito, M. Morita, K. Takezawa, Michio Motegi, K. Matsubara
{"title":"Proposal for management of investigation boring work using microtremor data: - From prediction of drilling depth to adequacy evaluation for engineering bedrocks -@@@－ボーリング深度の事前予測から工学的基盤の妥当性評価まで－","authors":"M. Yamada, Y. Ito, M. Morita, K. Takezawa, Michio Motegi, K. Matsubara","doi":"10.3208/JGS.9.739","DOIUrl":"https://doi.org/10.3208/JGS.9.739","url":null,"abstract":"","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"134 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122903509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Development of new direct shear apparatus and discussion on its effectiveness","authors":"Hiroki Ishikawa, Yujian Liu, Akitoshi Mochizuki, Syouji Okada, S. Sreng","doi":"10.3208/JGS.4.11","DOIUrl":"https://doi.org/10.3208/JGS.4.11","url":null,"abstract":"一面せん断定圧試験（CD試験）で生じる「供試体とせん断箱の側面摩擦問題」を避けるため，従来型試験機（以下では三笠型試験機と呼ぶ）の上部反力板上に2個の独立した空圧式ジャッキと荷重計を取り付けて，上部せん断箱にモーメントを加えるとともに，せん断箱を上，下に制御して，試験上必要な，水平および定圧条件を満足する方法を開発した。この装置を用いて密度を変えた豊浦砂の一連のCD試験を行い，従来型試験機によるCD試験，定体積試験（CU試験）結果と比較した。その結果，本研究で開発した「せん断中に上部せん断箱を上下させる装置」が一面せん断試験機の側面摩擦の解消に有効な方法であること，また定体積試験によるφ' 強度がφCD強度とほぼ一致すること，また三軸CD試験強度と比較して大差が無いこと等の結果が得られた。","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131235417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Sanagawa, H. Nishioka, M. Koda, Tatsuya Morino, T. Yonezawa, Hihumi Aoki
At the soft ground, the earthquakes generate large ground deformations. The large ground deformations displace the pile foundations, and induce the large pile forces at deep location. But it is not clear about the behavior of damaged piles, therefore, piles are generally designed not to be damaged by kinematic and inertial forces. In consequence, piles at soft ground have large diameter and it is difficult to cut off of the longitudinal bars in case of reinforced concrete piles at shallow location. The aim of this paper is to propose the economic seismic design code of pile foundations, and we make a study on the effect of cutting off of longitudinal bars reinforced concrete pile on lateral resistance under kinematic and inertial interactions by model tests and numerical simulations. The results of model loading tests confirmed that the damage at stepped rebar arrangement by ground deformation had no effect on lateral resistance, if the piles are not damaged by inertial forces. And it was possible to simulate the experimentally results by the static nonlinear analysis procedure with seismic displacement method. As a result, it indicated possibility of design considering the damage by ground deformations. Abstract At the soft ground, the earthquakes generate large ground deformations. The large ground deformations displace the pile foundations, and induce the large pile forces at deep location. But it is not clear about the behavior of damaged piles, therefore, piles are generally designed not to be damaged by kinematic and inertial forces. In consequence, piles at soft ground have large diameter and it is difficult to cut off of the longitudinal bars in case of reinforced concrete piles at shallow location. The aim of this paper is to propose the economic seismic design code of pile foundations, and we make a study on the effect of cutting off of longitudinal bars reinforced concrete pile on lateral resistance under kinematic and inertial interactions by model tests and numerical simulations. The results of model loading tests confirmed that the damage at stepped rebar arrangement by ground deformation had no effect on lateral resistance, if the piles are not damaged by inertial forces. And it was possible to simulate the experimentally results by the static nonlinear analysis procedure with seismic displacement method. As a result, it indicated possibility of design considering the damage by ground deformations.
{"title":"Effect of cutting off of longitudinal bars of reinforced concrete pile on lateral resistance under kinematic and inertial interactions","authors":"T. Sanagawa, H. Nishioka, M. Koda, Tatsuya Morino, T. Yonezawa, Hihumi Aoki","doi":"10.3208/jgs.10.33","DOIUrl":"https://doi.org/10.3208/jgs.10.33","url":null,"abstract":"At the soft ground, the earthquakes generate large ground deformations. The large ground deformations displace the pile foundations, and induce the large pile forces at deep location. But it is not clear about the behavior of damaged piles, therefore, piles are generally designed not to be damaged by kinematic and inertial forces. In consequence, piles at soft ground have large diameter and it is difficult to cut off of the longitudinal bars in case of reinforced concrete piles at shallow location. The aim of this paper is to propose the economic seismic design code of pile foundations, and we make a study on the effect of cutting off of longitudinal bars reinforced concrete pile on lateral resistance under kinematic and inertial interactions by model tests and numerical simulations. The results of model loading tests confirmed that the damage at stepped rebar arrangement by ground deformation had no effect on lateral resistance, if the piles are not damaged by inertial forces. And it was possible to simulate the experimentally results by the static nonlinear analysis procedure with seismic displacement method. As a result, it indicated possibility of design considering the damage by ground deformations. Abstract At the soft ground, the earthquakes generate large ground deformations. The large ground deformations displace the pile foundations, and induce the large pile forces at deep location. But it is not clear about the behavior of damaged piles, therefore, piles are generally designed not to be damaged by kinematic and inertial forces. In consequence, piles at soft ground have large diameter and it is difficult to cut off of the longitudinal bars in case of reinforced concrete piles at shallow location. The aim of this paper is to propose the economic seismic design code of pile foundations, and we make a study on the effect of cutting off of longitudinal bars reinforced concrete pile on lateral resistance under kinematic and inertial interactions by model tests and numerical simulations. The results of model loading tests confirmed that the damage at stepped rebar arrangement by ground deformation had no effect on lateral resistance, if the piles are not damaged by inertial forces. And it was possible to simulate the experimentally results by the static nonlinear analysis procedure with seismic displacement method. As a result, it indicated possibility of design considering the damage by ground deformations.","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133387199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Seismic behavior of reinforced soil wall combined with soil cement","authors":"J. Izawa, T. Saitoh, H. Itoh, M. Ueno, J. Kuwano","doi":"10.3208/jgs.2.73","DOIUrl":"https://doi.org/10.3208/jgs.2.73","url":null,"abstract":"筆者らは補強土壁の壁面部分に改良土を配置しジオグリッドと組み合わせる補強土工法の開発を進め，ここ数年で適用事例も伸ばしている。しかし，耐震性能に関しては未解明な部分が多く課題となっていた。そこで，本工法の耐震性能を把握することを目的として遠心模型振動実験を行った。その結果，従来のジオグリッドのみによる補強土擁壁や，改良土のみの擁壁と比較して高い耐震性を示すことが分かったが，最終的に改良土壁内にクラックが発生し破壊に至る可能性があることが分かった。このクラックは壁面パネルからのアンカーとジオグリッドを補強土壁内でオーバーラップさせることによって抑制できた。また，改良土に短繊維を混合することにより，引張り破壊後の残留強度の落ち込みを抑えることが出来，クラック発生を抑制できることが分かった。","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122348544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effects of vertical load of superstructure on piled raft foundation in sand subjected to static horizontal and moment load","authors":"K. Sawada, J. Takemura","doi":"10.3208/JGS.11.85","DOIUrl":"https://doi.org/10.3208/JGS.11.85","url":null,"abstract":"","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123952898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Failure mechanism of cement treated clay with tire chips and change of its permeability under shear deformation","authors":"Y. Kikuchi, T. Nagatome, Y. Mitarai","doi":"10.3208/JGS.1.19","DOIUrl":"https://doi.org/10.3208/JGS.1.19","url":null,"abstract":"本研究では，マイクロフォーカスX線CTスキャナを用いて，ゴムチップ混合固化処理土供試体の密度分布や内部構造を観察した。また，ゴムチップ混合量の異なるいくつかの供試体について一軸圧縮試験の途中段階でX線CTスキャンや透水試験を行うことにより，せん断中の供試体内部の亀裂の進展状況と透水係数の変化について検討した。この結果，ゴムチップを混合することによって固化処理土の靭性が増し，透水係数の上昇が抑えられることを示した。","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121035533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kyu Lee, T. Koyama, Y. Ohnishi, Hideaki Furukawa, Takaji Kobayashi
Recently, overflow due to the heavy rainfall causes the collapse of the river levee, as a result, serious flooding and damage. It is necessary to investigate the failure mechanism of the river levee due to the heavy rain and evaluate the stability of the river levee. According to the guideline for the design of the river levee, the seepage failure of the river levee is conventionally evaluated by the minimum safety factor of sliding, which is obtained from the circular arc calculation with the result of the seepage analysis. In this paper, the seepage failure caused by the overflow was mainly focused and simulated by newly developed coupled stress-water flow simulation code. In the numerical simulations, the seepage under saturated-unsaturated conditions considering rainfall, change of the water level, and overflow due to the heavy rain was solved and combined with the mechanical simulations. Stress and flow (seepage) were coupled only in the saturated zone and the coupled processes were not considered in the unsaturated zone. The simulation results clearly show the failure mechanism of the river levee by overflow.
{"title":"Coupled stress-flow simulations for the river levee considering overflow","authors":"Kyu Lee, T. Koyama, Y. Ohnishi, Hideaki Furukawa, Takaji Kobayashi","doi":"10.3208/JGS.4.1","DOIUrl":"https://doi.org/10.3208/JGS.4.1","url":null,"abstract":"Recently, overflow due to the heavy rainfall causes the collapse of the river levee, as a result, serious flooding and damage. It is necessary to investigate the failure mechanism of the river levee due to the heavy rain and evaluate the stability of the river levee. According to the guideline for the design of the river levee, the seepage failure of the river levee is conventionally evaluated by the minimum safety factor of sliding, which is obtained from the circular arc calculation with the result of the seepage analysis. In this paper, the seepage failure caused by the overflow was mainly focused and simulated by newly developed coupled stress-water flow simulation code. In the numerical simulations, the seepage under saturated-unsaturated conditions considering rainfall, change of the water level, and overflow due to the heavy rain was solved and combined with the mechanical simulations. Stress and flow (seepage) were coupled only in the saturated zone and the coupled processes were not considered in the unsaturated zone. The simulation results clearly show the failure mechanism of the river levee by overflow.","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129091267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Evaluation of the effect of inclination of reinforcement on horizontal bearing capacity of geo reinforcing type foundation","authors":"J. Izawa, H. Kusaka, N. Nakatani, M. Ueno, Hiroshi Sato, J. Kuwano","doi":"10.3208/JGS.3.55","DOIUrl":"https://doi.org/10.3208/JGS.3.55","url":null,"abstract":"地盤補強型基礎工法は，道路橋梁基礎および送電鉄塔基礎の支持力確保のためのコストダウン工法として開発され，実適用によりコスト縮減に効果を上げてきた。本研究は，近年増加している径5ｍ以上の大口径深礎に対応した工法への改良に向けた，合理的な補強形態の把握を目的としている。水平荷重を受けた大口径深礎は剛体的に回転すると考えられ，回転に対して有効に補強効果を得られる角度で補強材を打設する必要がある。そこで補強材打設角度に着目し，その影響について遠心場水平載荷試験にて検証を行った。実験から水平荷重を受ける地盤補強型基礎工法の補強メカニズムを明らかにした。また，打設角度45°で補強材に効率的に軸力が発生する補強形態となり補強効率は最適になった。この補強材に作用する軸力は，補強材に作用する周辺地盤からの拘束圧に対する打設角度の影響と，地盤の最小主ひずみ方向と補強材打設方向の差を考慮する補正係数f(θ)を評価することにより算出できた。これらの結果をもとに，梁バネモデルを用いた地盤補強型基礎の抵抗モーメント評価法を示した。","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129162730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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